Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D12/00—Displacing liquid, e.g. from wet solids or from dispersions of liquids or from solids in liquids, by means of another liquid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D9/00—Crystallisation
  • B01D9/004—Fractional crystallisation; Fractionating or rectifying columns
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D9/00—Crystallisation
  • B01D9/004—Fractional crystallisation; Fractionating or rectifying columns
  • B01D9/0045—Washing of crystals, e.g. in wash columns
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C63/00—Compounds having carboxyl groups bound to a carbon atoms of six-membered aromatic rings
  • C07C63/14—Monocyclic dicarboxylic acids
  • C07C63/15—Monocyclic dicarboxylic acids all carboxyl groups bound to carbon atoms of the six-membered aromatic ring

Definitions

• the present invention relates to a method for replacing a first dispersion medium of a raw slurry composed of a first dispersion medium and terephthalic acid crystals with a second dispersion medium. More specifically, the raw slurry of the first dispersion medium and the terephthalic acid crystals, which are obtained from the liquid phase oxidation reaction or obtained by catalytic hydrogenation or recrystallization treatment of crude terephthalic acid, and the terephthalic acid crystals containing a large amount of impurities.
• the present invention relates to a dispersion medium replacement method for efficiently replacing the first dispersion medium with the second dispersion medium, and is a method suitable for producing high-purity terephthalic acid.
• terephthalic acid p? P such as alkylbenzene? Manufactured by liquid phase oxidation reaction of a phenylene compound.
• a catalyst such as cobalt or mangan using acetic acid as a solvent, or in the presence of a promoter such as a bromine compound or acetaldehyde, p?
• Crude terephthalic acid is obtained by liquid-phase oxidation of a phenylene compound, and then the crude terephthalic acid is purified to obtain high-purity terephthalic acid.
• the crude terephthalic acid is dissolved in a mixed solvent of acetic acid, water, acetic acid and Z water at high temperature and high pressure to perform catalytic hydrogenation, decalization
• a mixed solvent of acetic acid, water, acetic acid and Z water at high temperature and high pressure to perform catalytic hydrogenation, decalization
• Various methods are known, such as a method of Bonylation treatment, oxidation treatment and recrystallization treatment, or a method of high temperature dipping treatment of a dispersion in which terephthalic acid crystals are partially dissolved.
• liquid phase oxidation Even when the dispersion medium of the reaction product liquid and the solvent used for purification are the same, when the raw slurry consisting of the liquid phase oxidation reaction product liquid or the first dispersion medium and terephthalic acid crystals is purified, 4CBA or Most of oxidation intermediates such as p-TOL or coloring-causing substances are dissolved in the dispersion medium at high temperatures. When these impurities are dissolved and the raw slurry consisting of the liquid phase oxidation reaction product liquid or the first dispersion medium and terephthalic acid crystals is cooled to around 100 ° C, these impurities are taken into the terephthalic acid crystals. It is difficult to obtain high purity terephthalic acid.
• Centrifugation is the most commonly used method for separating crystals and dispersion medium from a slurry, and is a raw slurry comprising a liquid phase oxidation reaction product liquid or a first dispersion medium and terephthalic acid crystals. In this case, the centrifugation method is widely used.
• a first dispersion medium and a raw slurry having crystal power of terephthalic acid are introduced into a basket rotating at high speed, the first dispersion medium is overflowed from the upper part, and the crystals are guided to the lower part. It is known that operation at high temperature and high pressure involves some difficulties due to structural and functional limitations of the centrifuge.
• a method has been proposed in which a first apparatus can separate the first dispersion medium and the crystal and reslurry with another dispersion medium under high temperature and high pressure.
• a dispersion medium displacement apparatus using the precipitation action of terephthalic acid crystals due to gravity is used.
• a raw slurry consisting of the first dispersion medium and terephthalic acid crystals is introduced from the upper part of the apparatus, a second dispersion medium is introduced from the lower part of the apparatus, and a substitution slurry consisting mainly of terephthalic acid crystals and the second dispersion medium from the lower part.
• Unplug This is a method of using a device that draws out the first dispersion medium mainly from the top.
• a problem common to these apparatuses is that when supplying the original slurry consisting of the first dispersion medium and terephthalic acid crystals into the upper end of the apparatus, the terephthalic acid crystals in the slurry are uniformly dispersed in the horizontal direction. It is difficult to do. If it is not evenly distributed in the horizontal direction, mixing in the vertical direction of the displacement device cannot be suppressed as a result.
• the performance of the dispersion medium replacement device is how to suppress the movement of the first dispersion medium supplied to the upper part to the lower part, and it is necessary to suppress the mixing in the vertical direction.
• the terephthalic acid crystal When the terephthalic acid crystal is supplied non-uniformly to the uppermost shelf in the apparatus provided with the perforated plate-like shelf, the portion of the portion where the terephthalic acid crystal is concentrated is supplied In particular, the flow from the bottom to the bottom is induced, and conversely, an upward flow occurs in the part where terephthalic acid crystals are not supplied. This accelerates mixing between the top and bottom of the shelf and degrades the stage efficiency. In addition, in an apparatus equipped with a perforated plate shelf, uneven supply of terephthalic acid crystals may cause blockage of the shelf holes.
• Patent Document 1 Specification of British Patent No. 2014985
• Patent Document 2 Japanese Patent Publication No.57-53431
• Patent Document 3 JP-A-8-231465
• the present invention can uniformly disperse the terephthalic acid crystals in the slurry in the horizontal direction when supplying the raw slurry composed of the first dispersion medium and the terephthalic acid crystals, and can be operated stably for a long time. It is an object of the present invention to provide a dispersion medium replacement method.
• the inventors have difficulty in uniformly dispersing terephthalic acid crystals in the horizontal direction in a conventional distributor in which the flow path of the unit injection port is narrowed, and long-term operation is also difficult. Attention was paid to intensive research. As a result, we came up with the idea of using centrifugal force as the driving force for dispersion, and found a method for replacing the dispersion medium using a cyclone nozole with a simple structure and good dispersion.
• the raw slurry composed of the first dispersion medium and the terephthalic acid crystals is supplied to the cyclonic nozzle disposed in the upper part of the replacement tank of the dispersion medium replacing device, and flows out from the cyclonic nozzle.
• the raw slurry is supplied from the lower part of the replacement tank and brought into contact with the second dispersion medium rising in the replacement tank, and the replacement slurry mainly consisting of terephthalic acid crystals and the second dispersion medium is extracted from the lower part of the replacement tank.
• the first dispersion medium is mainly extracted from the upper part of the replacement tank.
• the dispersion medium replacement method is a method for replacing the original slurry from a tangential direction to a cylindrical part having an axis in a vertical direction of a cyclonic nozzle. And a dispersion medium replacement method in which the raw slurry that moves in a circular motion is caused to flow out from the opening on the lower surface in the vertical direction of the cylindrical portion and is dispersed in the second dispersion medium.
• FIG. La is a perspective view showing an example of a cyclonic nozzle
• FIG. Lb is a cross-sectional view taken along line V-V in FIG. La.
• FIG. 2a is a perspective view showing another example of a cyclonic nozzle
• FIG. 2b is a cross-sectional view taken along line V-V in FIG. 2a.
• FIG. 3a is a perspective view showing another example of a cyclonic nozzle
• FIG. 3b is a cross-sectional view taken along line V-V in FIG. 3a.
• FIG. 4 is a schematic view showing a state in which the raw slurry is distributed from the tangential direction of the ring-shaped header to the cyclone-shaped inlet.
• FIG. 5 is a schematic diagram showing an example of a dispersion medium replacement device.
• FIG. 6 is a perspective view showing a cyclonic nozzle.
• FIG. 7 is a graph showing the slurry concentration distribution in the tank of Reference Example 1.
• FIG. 8 is a graph showing the slurry concentration distribution in the tank of Comparative Example 1
• FIG. 9 is a schematic view showing another example of a dispersion medium replacement device.
• FIG. 10 is a graph showing the slurry concentration distribution in the tank of Example 1.
• a cyclone-shaped nozole is used in the dispersion medium replacement apparatus of the present invention. Examples of these are shown in FIGS. 1 to 3, but the structure and shape of the cyclone-shaped nozole are not limited to these as long as the conditions described below are satisfied.
• the cyclonic nozzle has a raw slurry supply section and a cylindrical section connected to the supply section.
• the cylindrical portion has an axis in the vertical direction (a cylindrical portion extending in the vertical direction), and an opening is provided on at least the lower surface of the vertical upper surface and the lower surface of the cylindrical portion.
• the supply section is provided so as to supply the raw slurry in the tangential direction of the cylindrical section.
• the raw slurry is supplied so as to circularly move along the inner wall surface of the cylindrical portion.
• the circularly moving raw slurry moves toward the inner wall surface of the cylindrical part by centrifugal force, and the raw slurry that moves circularly is filled near the inner wall surface of the cylindrical part.
• the raw slurry descends while moving in a circular motion and flows out while moving in a circular motion from the opening on the lower surface in the vertical direction of the cylindrical portion.
• the raw slurry flowing out from the cylindrical part is dispersed over a wide range in the horizontal direction by centrifugal force.
• the diameter of the opening can be made sufficiently larger than the diameter of the conventional distributor, there is no blockage even during long-term operation.
• a raw slurry supply section and a cylindrical section having a shaft in the vertical direction connected to the raw slurry supply section are connected, and the supply section is connected to supply the raw slurry in a tangential direction of the cylindrical section.
• An opening may be provided on the upper surface in the vertical direction of the cylindrical portion, and it may or may not be provided.
• An opening for allowing the raw slurry to flow out is provided on the lower surface in the vertical direction of the cylindrical portion.
• the supplied raw slurry can be circularly moved along the inner wall surface of the cylindrical portion.
• the structure of the cylindrical portion is not particularly limited as long as it does not hinder the circular motion of the raw slurry.
• the supplied raw slurry is along the inner wall of the cylinder In order to make a circular motion, it is preferable that the cylindrical part is connected to the supply part so as to supply the tangential force raw slurry of the cylindrical part.
• the opening for causing the circularly moving raw slurry to flow into the dispersion medium replacement device is formed on the lower surface in the vertical direction of the cyclone-shaped nozzle, for example, as shown in FIGS. Provided by a plate. In order to suppress the dispersion of the raw slurry from the upper surface of the cylindrical portion, it is not necessary to provide an opening on the upper surface (FIG. 3).
• a raw slurry composed of a first dispersion medium and terephthalic acid crystals is supplied from a cyclonic nozzle located at the top of the dispersion medium replacement apparatus, and the second dispersion medium is replaced with the dispersion medium.
• the replacement slurry consisting mainly of terephthalic acid crystals and the second dispersion medium is extracted from the lower part of the dispersion medium replacing apparatus, and the first dispersion medium is mainly extracted from the upper part.
• the first dispersion medium is an oxidation reaction mother liquor, and acetic acid is the main component.
• the concentration of terephthalic acid in the raw slurry is preferably 10 to 40% by weight.
• the concentration of acetic acid in the first dispersion medium is preferably 70 to 100% by weight.
• the temperature supplied to the dispersion medium replacement device is preferably 80 to 220 ° C.
• the second dispersion medium is acetic acid or pure water optionally containing pure water.
• the water concentration in the second dispersion medium is preferably 50 to 100% by weight.
• the second dispersion medium is pure water.
• the first dispersion medium of the raw slurry is water in which impurities are dissolved during recrystallization, and the second dispersion medium is pure water.
• the concentration of terephthalic acid in the raw slurry is preferably 10 to 40% by weight.
• the temperature supplied to the dispersion medium replacement device is preferably 100 to 220 ° C.
• the number of cyclone nozzles relative to the cross-sectional area of the dispersion medium displacement device, in which the area of the raw slurry outlet (the opening on the lower surface of the cylindrical portion) of the cyclonic nozzle is preferably 0.03 to 0.8 m 2 . Les, Shi preferred that is a 0.3 to 2 pieces / m 2.
• the number of cyclone nodules is determined from the size of the dispersion medium replacement device used and the range (dispersion area) in which the raw slurry that has flowed out of the cyclone nozzle force is dispersed. Usually, the effective dispersion area of one cyclone-shaped nozzle is 3m 2 or less.
• the number of nozzles per unit cross-sectional area of the dispersion medium replacement device Is 0.3 / m 2 or more.
• the number of nozzles per unit cross-sectional area of the dispersion medium replacement device Is 0.3 / m 2 or more.
• the raw slurry supplied to the ring header is supplied to each cyclone nozzle.
• the raw slurry is preferably supplied to each cyclone nozzle along the tangential direction of the ring-shaped header. In this way, the raw slurry is supplied to the cyclone-shaped nozzle while maintaining the circular motion in the ring-shaped header, and the raw slurry supplied to the cyclonic nozzle is maintained inside the dispersion medium replacing device while maintaining the circular motion. Outflow and disperse with circular motion.
• Such a vortex nested structure allows efficient replacement of the first dispersion medium with the second dispersion medium. Furthermore, when such a ring-shaped header is employed, even if the raw slurry flow rate supplied to the ring-shaped header changes, the raw slurry is evenly supplied to each cyclone-shaped nozzle. Such an effect cannot be obtained by limiting the flow rate with an orifice or valve.
• FIG. 9 shows an example of a dispersion medium replacement device.
• the raw slurry (terephthalic acid crystal Z first dispersion medium) is supplied through a supply valve 14 and a supply port 15 to a cyclonic nozzle 16 disposed at the top of a replacement tank 12 made of stainless steel or the like.
• the cylinder of the cyclonic nozzle 16 is preferred that the diameter of the replacement tank 12 is 0.3 to 7 m and the height is preferably 1 to 20 m.
• the diameter of the part is preferably 0.:! To lm.
• the supply speed of the raw slurry to the cyclonic nozzle 16 is not particularly limited as long as the raw slurry flows out of the cyclonic nozzle 16 while circularly moving, but when the replacement tank 12 and the cyclonic nozzle 16 have the above sizes, It is preferably 0.5 to 50 tZh.
• the second dispersion medium is preferably supplied at a speed of 0.3 to 40 tZh through the valve 17 from the second dispersion medium supply port 18 disposed in the vicinity of the bottom of the replacement tank 12.
• the supplied second dispersion medium rises in the substitution tank 12.
• the raw slurry that has flowed out of the cyclonic nozzle 16 comes into contact with the second dispersion medium rising in the substitution tank 12 and is uniformly dispersed in the horizontal direction in the second dispersion medium while moving in a circular motion.
• the dispersed terephthalic acid crystal settles in a phase rich in the second dispersion medium due to gravity, and a replacement slurry consisting of terephthalic acid crystals and mainly the second dispersion medium accumulates in the lower part of the substitution tank 12.
• This replacement slurry is extracted from the replacement slurry extraction port 19 using an extraction pump 13.
• the temperature in the replacement tank 12 is preferably maintained at 80 to 180 ° C.
• the first dispersion medium is pushed upward by the supplied second dispersion medium, and is discharged out of the apparatus through the first dispersion medium outlet port 20.
• the state of dispersion in tank 1 was examined using the experimental apparatus for observing the dispersion state shown in Fig. 5.
• a water slurry of sand with an adjusted particle size (average particle size 95 ⁇ m) was used as the raw slurry (sand concentration: 35% by weight).
• the raw slurry was charged into the tank 1, and the raw slurry was circulated through the electromagnetic flow meter 4 and the flow rate adjusting valve 3 to the raw slurry supply port 5 using a circulation pump 2 so that sand was not accumulated at the bottom.
• the circulated raw slurry was supplied to the cyclone-shaped nozzle 6 and discharged and dispersed inside the tank 1 while maintaining circular motion.
• the structure of the cyclonic nozzle 6 is shown in FIG.
• a raw slurry supply unit 11 is connected to the cylindrical part 10 so that the raw slurry is supplied from the tangential direction.
• Opening 8 opening diameter: 0.58 m
• opening 9 opening diameter: 0 ⁇ 43m.
• the slurry was continuously circulated for 6 hours. No blockage of the cyclonic nozzle 6 occurred.
• the distribution of the slurry concentration in tank 1 was measured in the same manner as in Reference Example 1 except that an L-shaped pipe with the opening facing downward was used as the feed nose instead of the cyclonic nozzle 6. The results are shown in the graph of Fig. 8. As is clear from Fig. 8, the sand dispersion was uneven in the horizontal direction.
• the raw slurry was circulated in the same manner as in Comparative Example 1 except that a big tail type dispersing device was installed at the tip of the L-shaped feed nose of Comparative Example 1. Occlusion occurred 10 minutes after the start of circulation.
• Dispersion medium replacement was performed using an apparatus having the same structure as in FIG. A stainless steel sealed container with an inner diameter of 30 cm and a height of 100 cm was used as a replacement tank.
• a stainless steel airtight container was filled with water at 100 ° C., and a raw slurry containing 30% by weight of terephthalic acid as a first dispersion medium was supplied at 770 kg / h to a cyclone-shaped nozole similar to Example 1.
• Water was supplied as a second dispersion medium from the lower part of the replacement tank at 560 kg / h. From the lower part of the substitution tank, terephthalic acid crystals and substitution slurry, which is the second dispersion medium, were extracted, and the first dispersion medium was mainly extracted from the upper part of the substitution tank. Dispersion medium replacement was performed continuously for 1 week, but no troubles such as clogging occurred.
• Sampling Nozzle 21 was used to sample the slurry in the replacement tank at different horizontal positions (height 40 cm above the bottom of the replacement tank), and the slurry concentration (concentration of terephthalic acid crystals in the slurry) was measured. As shown in the graph of Fig. 10, the terephthalic acid crystals were uniformly dispersed in the horizontal direction. Industrial applicability
• the dispersion medium replacement method of the present invention uses a cyclone-shaped nozzle that satisfies specific conditions, the terephthalic acid crystals in the slurry are added when supplying the original slurry consisting of the first dispersion medium and the terephthalic acid crystals. It can be dispersed uniformly in the horizontal direction, and stable long-term operation is possible.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Dispersion Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Cyclones (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Related Parent Applications (2)

Related Child Applications (2)

Publications (1)

Family

ID=38831664

Family Applications (1)

Country Status (9)

Families Citing this family (3)

Citations (7)

Family Cites Families (14)

• 2007
  • 2007-06-08 CN CN2007800215641A patent/CN101472876B/zh not_active Expired - Fee Related
  • 2007-06-08 KR KR1020087030056A patent/KR101436646B1/ko active IP Right Grant
  • 2007-06-08 CN CN201210096602.2A patent/CN102671424B/zh not_active Expired - Fee Related
  • 2007-06-08 ES ES12155582.5T patent/ES2575665T3/es active Active
  • 2007-06-08 EP EP12155582.5A patent/EP2455360B1/de active Active
  • 2007-06-08 WO PCT/JP2007/061667 patent/WO2007145149A1/ja active Application Filing
  • 2007-06-08 EP EP07767086.7A patent/EP2028175B1/de active Active
  • 2007-06-08 US US12/304,415 patent/US8247604B2/en active Active
  • 2007-06-08 ES ES07767086.7T patent/ES2615125T3/es active Active
  • 2007-06-08 JP JP2008521181A patent/JP5291459B2/ja active Active
  • 2007-06-12 TW TW096121091A patent/TWI427060B/zh active
• 2008
  • 2008-12-11 MY MYPI20085028A patent/MY149967A/en unknown

Patent Citations (7)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events